The posterior cruciate ligament in total knee surgery. Save, sacrifice, or substitute?

To determine the role of the posterior cruciate ligament in total knee arthroplasty, 242 consecutive primary total knee arthroplasties were included in 1 of 3 sequential groups. Group I included 77 Press Fit Condylar total knee replacements in which the posterior cruciate ligament was completely released from its tibial attachment. In Group II, there were 80 Press Fit Condylar total knee replacements in which the posterior cruciate ligament was retained. Group III consisted of 85 total knee replacements with a posterior cruciate-substituting device (Insall-Burstein II). All patients were observed at least 2 years and evaluated by the Knee Society's Clinical and Functional Scoring System, including a radiographic evaluation. No differences were found between the posterior cruciate ligament sacrificed group and the posterior cruciate ligament preserved group. The 1 significant difference among the 3 groups was in range of motion (ROM). Groups I and II averaged 103 degrees and 104 degrees motion respectively, whereas Group III, the posterior cruciate-substituting group, averaged 112 degrees (p = 0.001). In addition, only in Group III was the lower 95% confidence limit of the mean ROM > 90 degrees. These findings suggest that preserving the posterior cruciate ligament does not consistently lead to improved functional ROM. The posterior cruciate ligament-substituting device historically has demonstrated excellent survivorship and appears to offer greater ROM.